Any parcel of land in Alberta can be located by its legal land description. Legal land descriptions are based on the Alberta Township Survey (ATS) system. The ATS is a grid network dividing the province into equal-sized parcels of land.
Under the ATS, land is designated as being west of the 4th, 5th, or 6th Meridians (110°, 114°, 118° west longitude, respectively).
Between meridians are six-mile-wide columns called ranges. Ranges are numbered consecutively from east to west starting at Range 1 west of each meridian.
Townships are six-mile-wide rows that intersect ranges and are numbered consecutively from Township 1 at the Montana border to Township 126 at the Northwest Territories border. The term township also describes the six-by-six mile square formed by the intersection of ranges and townships.
Sections, quarters and legal subdivisions
Townships are divided into 36 sections, each section measuring one-by-one mile. Sections can then be divided into quarters (NE, NW, SE, SW), or into 16 legal subdivisions (LSD), as indicated.
The legal description of the section highlighted in the diagram above would be written as:
1 - 87 - 18 - W4
Sec. Twp. Rge. Meridian